Standard Deviation Calculator
Population and sample standard deviation of a data set.
Worth Knowing
Standard deviation measures how spread out data is around its mean, in the same units as the data itself. The key choice is population versus sample: dividing by n gives the population value, while dividing by n−1 (Bessel's correction) gives the sample estimate, which corrects a bias that appears when you're generalizing from a subset. Use the sample version unless your data genuinely covers the entire group you care about.
How to Use
- Enter Numbers into the Standard Deviation Calculator above.
- Your result appears instantly as you type — there's no submit button or page reload.